On Fri, Aug 08, 2003 at 07:20:49PM -0700, Tim Rowledge wrote:
> "Joshua 'Schwa' Gargus" <schwa at cc.gatech.edu> wrote:
> 
> > I was curious where Ephemerons came from, and in case others are too, 
> > here's a reference:
> > 
> > Ephemerons: a new finalization mechanism; Barry Hayes; OOPSLA 1997,
> > pages 176-183
> I have a feeling PPS got a patent for the idea.

A google on "ephemerons" turns up lots of interesting references,
including a emacs implementation (fully credited as per above), as
well as an explanation of the topic by Eliot Miranda.

Google turns up no references to patents and no indication that anyone
was concerned about IP when the emacs implementation was released.

>From the emacs source:

/* The concept of ephemerons is due to:
 * Barry Hayes: Ephemerons: A New Finalization Mechanism. OOPSLA 1997: 176-183
 * The original idea is due to George Bosworth of Digitalk, Inc.
 *
 * For a discussion of finalization and weakness that also reviews
 * ephemerons, refer to:
 * Simon Peyton Jones, Simon Marlow, Conal Elliot:
 * Stretching the storage manager
 * Implementation of Functional Languages, 1999
 */

By the way, I appreciate finding references like this in Squeak class
comments.  I don't have any real background in computer science, so
Squeak is sort of my living textbook. It's nice to learn where some of
the concepts come from.

Dave